8b mine begins with very long and narrow lower-surface part, that several times crosses the leaf: Phytomyza kaltenbachi

8c mine begins with a knot or spiral, or a short lower-surface corridor (may be along the midrib) => 9

9a lower-surface section mostly a densely wound spiral => 10

9b lower-surface section a corridor of a few mm => 12

10a frass in two rows; corridor not associated with the leaf margin; northern Europe and the mountains of central Europe: Phytomyza pulsatillae

10b frass in pearl chains of strings at one side of the corridor; parts of the corridor follow the leaf margin; south and central European lowlands => 11

11a lower-surface section a more or less tortuous, epidermal, silvery corridor with a fine black frass line: Phytomyza dalmatiensis

11b lower-surface section a dense knot in the sponge parenchyma, finally forming a small full depth transparent patch: Phytomyza rectae

12a frass in long threads that over long tracks lie at the same side of the corridor; mine usually begins in the tip of a leaflet; in upper-surface part of the mine the corridor sides are smooth: Phytomyza vitalbae

12b frass in pearl chains, alternating along the sides of the mine, sometimes almost seeming central; mine less often beginning in the tip of a leaflet; corridor sides in upper-surface part of the mine irregularly eaten out: Phytomyza fulgens